Basic open-hearth furnace.



NASWlTH. msm @PEN #EARTH fummo@ n APPLlCATlON FlLED APRA-.711916. Y 1r vm m g faiute Mar. f, 91 1 I s. NAISMITH. BASIC OPEN HEARTH FURNACE. APPLICATION FILED APHAI?. I9I6.

Patented Mam?, 19N.

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S. NAZSMITLM BASIC OPEN H EARTH FURNACE.

atented May. 27, '19W APPLICATGN FILED A PR. I?, 1916.

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SAMUEL NAISMITH, OF CHICAGO, ILLINOIS.

BASIC OPEN-HEARTH FURNACE.

` Specicatioii of Letters Patent.

Patented Main 23?,

Application med 'April 1'?, 191e. serial No. 91,603.

To all w/wm t may concern:

Be it known that I, SAMUEL NAIsMrrH, a citizen of the United States, residing at Chicago, in the county of Cook and State ofIllinois, have inventednew andguseful Improvements in Basic Open-Hearth Furnaces, of which the following is a `specification.

My invention relates more particularly to basic 'open hearth and reheating f furnaces used for metallurgical purposesv and has for its object a new and useful improvement.

for the preservation ofthe slag-line and means for supporting thefurnace walls adjacent thereto. It is a further Object of my invention to provide an improved means to .prevent the basic-and acid linings of the constructed of acid. material, usually silica brick. At thejoint where the hearth joins the remainder of the furnace there is placed between the two materials, to rel tard their luxing, a neutral joint'of passive material, usually chromite. That part of the furnace at and near the neutral joint is known as the slag-line; the interior of the furnacev at' the slagline is provided 4with a. bank of magnesite or the like, for

the purpose of col'nbating. the attack of the slag on the walls Vofthe hearth.

The slag, which is usually a few inches in depth, is composed of' the impurities in the metal, scrap iron, etc;, caused by oxidation, and always contains magnesia, which makes it very pernicious and extremely de structive to the walls of thehearth'.` atthe slag-line, and whenihigh in silica, as is frequently the case, it attacks the' hearth and banks and undermines the walls of the furnace, causing them to collapse. This'often occurs while the heat of steel is in the furnace. lt then becomes necessary7 to shut off the gas while the walls are being re.- placed andl in the meantime the heat of steel becomes chilled andmust be again remelted, thus resulting in considerable delay and expense.

The slag-line, which as net'orc stated, is that part .of the. furnace at. and near the point where the hearth joins the remainder of the furnace, is composed of grain maglie site and .magnesite brick, which, at best, are 'unsatisfactory and expensive, for which such a construction the slag' line must be banked, repaired or fettled after every heat, which is every `nine and one-half (9g) hours, with burnt doiomite,grain magnesite or some other basic refractory niete-y rial, and set at a high temperature before the furnace is again -in condition te 4receive the next charge. This method is expensive and results inv considerable delay. my invention the necessity of banking or repairing` after every heat is eliminated, as I place a water cooler or series of water coolers in the wall of the furnace at the slag-line, adjacent to the banks nn.- terial,` as a result of which the walls and basic material at or near this point are kept cool and in such condition as to withstand the pernicious attack and was-h of the slag, and the walls from being eaten out or undermined. l

In basic open hearth furnaces the hearth, as before stated, is lined and banked with basic material, while the side walls androof of the furnace are constructed of acid material, usually silica brick. lilith the intense heat within such furnace, particularly when charged with a. spray of iron oxid, the acid and basic materials will flux or unite, and. infact, when the silica brick melts, the acid runs down and cuts out the basic material pretty much as hot water would Snow. lilith a view of eliminating this in'thc present constructions, there is utilized a neutral joint at the slagline of chromite or other passive material, between the silica brick walls, the basicbanlrs and walls of the hearth, but this method is unsatisfactory and expensive. With my in vcntion thc chromite joint is eliminated en tirely, as the water cooler serves as a joint in place of the chromite and keeps the basic and acid materials cool and prev nrs any uxing or the melting of the silica brick, and the acid from the brick running down into. the basic materialln' the' construction disclosed in the aecom ranvino drawings .the vweight' of the .f h t1 D -With fir' and above the walls of the hearth the two materials are prevented from disintegration, and the supporting means for the silica walls kept cool and protected.

The water coolers are readily detachable, so that in the event any of them should hap pen to give way they can be readily and quickly removed andreplaced with'oht the necessity of shutting off the gas or allowin` the heated steel to become chilled.

he above and other features of novelty, advantages and capabilities will become ap parent from the detail description of the accompanying drawings, in which I have illustrated a practical embodiment 'of the invention, but the construction there shown is to be understood as illustrative only, and

f not as deining the limits of the invention.

Figure 1 is an elevation showing a part of the front of a furnace embodying one `for1n of my invention.

Fig. 2-is an elevation of a back wall.

F 1g. 3 is a vertical sectional View of such portion of the fu rnacc.

Fig. L is a longitudinal view in horizontal section ot the same, and

Fig. 5 is a detail perspective view of one of the water coolers apart from the furnace, showingthe connections therewith.

Referring to the drawings in detail, the air ports are shown at 10 and the gas orts at 11, which are typical of a furnace' o this type. The hearth 12, which is of the usual form of construction, is supported on a suitable trarne as shown and comprises a layer of second grade brick 13, a layer of rst grade brick 14, a layer of magnesite brick l5, which is extremely expensive as it is imported. from Austria, and which, at the present time, is difficult to obtain owing to the fact that the supply in this country is about exhausted. The layer of inagnesite brick 15 is provided with a Substantial lining of grain magnesite or dolomite 16. The hearth at one of its lower sides is provided with the usual tapping opening 17 for discharging the steel after it has been properly treated. This opening, of course, has the usual closure. The entire furnace is bound together at the sides and ends by a series of buck stays 18, which are connected together at their tops by means of rods 19 and at their lower edges by the cross-beams 20. Spaeed above the upper edge of the walls of the hearth. 12 at the front, sides andA back of the furnace is an angle iron 21, (best shown in Fig. 3) rigidly secured to the buck stays 18 by any suitable'means," such as the bolts shown. Constructed on and supported by these angle irons 21 are the side walls 22 of the furnace, which are made of silica brick. Connecting with the upper edge of the side walls 22 is the arch roof 23, which roof is carried by andsupported on the channels 24, which are suspended` by means of the rods 25 from the upper channels 26, which latter channels are supported by means of the buck stays 18. Within the space between the upper edge of the walls of the hearthl and the lower edge of the side walls 22 is placed a waterl cooler or series of water coolers 27. These are set in toward the interior of the furnace so asto be adjacent to the lining or banks 28 of the furnace. This is a portion of the furnace which is most severely attacked by the slag by rea- ,son of its composition and washing action,

and is the point where failure ,of the furnace usually occurs, and, with the metallurgical furnaces new in use this' part becomes damaged and burnedfout to an appreciable extent during every heat, and for that reason must be repaired or fettled after each heat, which is every nine and one-half (9%) hours, or, as .is commonly said', must be banked after every heat, and from this arises the word banks as designating that particular part of the furnace. The banks, as before stated, are usually constructed of burnt dolomite, grain lmagnesite `or some other basic refractory material, and set at a' high temperature before being infcondition to receive the next charge. This method is expensive and resuits in delay, but with the water coolers of my invention placed adjacent to the banks, the burning out or eating` away of them by the slag is greatly reduced and the necessity of repairin fettling or banking after each. heat entire y eliminated. The upper sides ofthe coolers 27 engage or are adjacent to the silica walls 22 and prevent these walls from melting and running downinto the banks or hearth and eating out the basic lining, and also protects the angle irons for supporting the walls 22. At the sides and back of the furnace the water coolers may be one continuous container, but at the front, `on account of the plurality of doors, it is desirable that these be constructed of a series of coolers, as best shown in Figs. 2 and 4. A. circulation of cool water is going on through all of these coolers' While the urnace is in use. The cool water is iutroduced to the coolers at the bottom thereof by means of the pipes-29, and discharged at the top of the coolers by means of the pipes 30. From this it will be seenthata circula-,j

hearth 12 are kept Icool, and that all the' advantages and features set forth for this isc reader@ invention., well as others, are readily accomplished by the use of ita Moreover, with my invention the layer of niegue-site bri lr l5, forming, a part 'of the "structiou allows 'lor the expansion and contraction ot the walls and prevents the breaking or disruption of the walls lfrom such forces i l". claini'.

l. ln'a basic open hearth furnace, a cooler positioned to serve as a neutral joint between the acid brick and basic lining to prevent Hurting.

it. lin a furnace of the class described, a series of readily removable Water coolers positioned in the -walls of the furnace at the slag line and near the lining thereof, and

means for producing a circulation of water thrmigh said coolers.

3, ln a furnace of the class described, a

serie et buck stays adjacent to the outer.

surface of the furnace, and means secured directly to 'the buch stays for supporting the Wall of the furnace to relieve the hearth of the 'weight thereof.

e. in a furnace of the class described, a series of buck stays adjacent to the outer surface of the furnace, an angle iron secured directly to the buck stays for supporting the Wall of the furnace.

5. In a basic open hearth furnace, a cooler at the slag line and adjacent to the banks for the purpose set forth.

6. n a basic open hearth furnace having a hearth and vertical Walls, rneaiis for supporting the vertical Walls independently of the hearth and a cooler adjacent to the supporting means for protecting the saine.

7. n a furnace, series of buch stays extending above the furnace, means connected directly with the hach' stays for supporting the vertical walls` independently of the hearth and means connecting with the buck stays for suspending the vroot` therefrom and supporting it independently of the vertical `Walls.

8. n the combination of a furnace provided With basic and acid linings, and water cooler positioned between said linings to4 prevent their during,

9. In a furnace, a series of buck stays extending above the furnace, an angle iron connected directly with the buck stays for supporting the if'ertical Walls, channel irons suspended troni and connected withthe up# per ends of the buck stays for supporting the roof.

In Witness whereof, hereunto subscribe my nainel to this specification. in the presence of two Witnesses.

Si'lllGIUEL NAISMTH.

W itnesses c CLARENCE J. lior'r'us, MARGARET 5. RYAN. 

